Electrode contact feedback system

ABSTRACT

A sensing assembly for sensing contact with an object is disclosed. The contact sensing assembly may comprise an elongate tubular body. An electrode may be connected to the elongate tubular body. A vibration element is operatively connected with the electrode and configured to deliver a vibration-inducing signal to induce vibration of the electrode. A sensor is configured to monitor the electrode for a perturbation in the induced vibration. The perturbation results from contact between the electrode and the object.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/216,908, filed 17 Mar. 2014, which claims the benefit of U.S.provisional application No. 61/798,138, filed 15 Mar. 2013, both ofwhich are hereby incorporated by reference as though fully set forthherein.

BACKGROUND

a. Field of the Disclosure

This disclosure relates to medical devices, including a catheterconfigured to provide an indication of contact between the catheter andtissue in a body.

b. Background Art

Catheters are used to perform a variety of tasks within human bodies andother bodies including the delivery of medicine and fluids, the removalof bodily fluids, and the transport of surgical tools and instruments.In the diagnosis and treatment of atrial fibrillation, for example,electrodes may be added to catheters for electrophysiological mapping ofthe surface of the heart and to deliver ablative energy to the surface,among other tasks. Catheters are typically routed to a region ofinterest through the vascular system. In a conventional approach, anintroducer is inserted through the skin surface and a sheath having aninner diameter greater than the outer diameter of the catheter isthreaded through the vasculature to a region of interest. The catheteris then moved longitudinally through the sheath to the region ofinterest either manually or through the use of various types of roboticcontrols such as electromechanical drive systems.

In the case of an electrophysiological mapping catheter,electrode-to-issue contact facilitates meaningful electrograms andaccurate mapping of the heart. In the case of ablation catheters,sufficient contact may be required for effective formation of ablativelesions in the tissue. A variety of mechanisms and techniques have beenemployed to determine contact between catheters and tissue, but theseare either complex and require additional components that increase thecost, size, and complexity of the catheter, or they are nonspecific anddifficult to interpret.

The disclosure herein has recognized a desire for a catheter that willminimize and/or eliminate one or more of the above-identifieddeficiencies.

BRIEF SUMMARY

The present invention generally relates to contact feedback mechanisms.Among other things, the present disclosure relates to contact feedbackmechanisms used in conjunction with catheters during cardiac ablation ordiagnostic procedures.

The disclosure is directed to contact feedback mechanisms, embodimentsof which are described in detail herein that include systems providingangular displacement on a spherical joint between an electrode body andits mounting structure. In one embodiment, adjacent to the sphericaljoint are compliant members, such as silicone, that are compressedaxially under load. The axial load creates a lateral or radial expansionof the compliant members. One or more of these compliant members arefitted with strain gauges or other sensor(s) that respond to thedisplacement of the material with a change in resistance. Withappropriate electronics, this change in resistance can be used as asignal or output to control an audible, visual, tactile (e.g.,vibratory), and/or other perceptible output system mounted in thecatheter handle or displayed on a monitor or other display device.

Further, the output could be tuned to respond to the magnitude of theload applied to the electrode. For example, if the output is used todrive a handle-mounted transducer that vibrates with an input signal, afrequency, amplitude, phase, and/or magnitude of this output mightchange to represent the relative displacement or force applied to theelectrode. Or, in a similar fashion, an LED mounted in the handle mightchange color or intensity as the electrode contact increases.

The disclosure further relates to contact feedback mechanisms in whichthe compliant members and strain gauges are replaced with piezoelectrictransducers that are configured to respond to input forces from anyelectrode deflection. In addition, the input on the piezoelectrictransducer can be amplified or concentrated with small evenly spacedrisers on the interface between the electrode and transducer.

The disclosure further relates to a contact sensing assembly of amedical device that may comprise a catheter including an elongatetubular body having at least a distal end, an electrode, a transducer,and a sensor. The electrode may be connected to the elongate tubularbody. The transducer may be driven by an electrical signal to vibratethe electrode at a defined frequency, such as a resonant frequency,which depends on the mechanical structure of the electrode. When theelectrode contacts an object, the amplitude, phase, and/or frequency ofthe resonant vibrations of the electrode may be dampened, and thedampening may be sensed either through the electrical drive signal orthrough a second independent transducer located near the vibratingelectrode.

The present disclosure further relates to a contact sensing assembly fora medical device that may comprise a catheter including an elongate bodyhaving a distal end, an electrode, an elastic or deformable member, anda sensor. The electrode may have an electrode tip and an electrode base.The electrode base may be connected to a distal end of the elongatebody. The electrode tip may be connected to the electrode base via aspherical joint. The spherical joint may allow the electrode tip to moverelative to the electrode base. The elastic or deformable member may bein contact with both the electrode tip and the electrode base and may beconfigured to elastically deform upon movement of said electrode tiprelative to electrode base. The sensor may be located on the member. Thesensor may be configured for measuring deformation of the member, wherea magnitude of the measured deformation of the member may be correlatedto a contact between the electrode tip and the object.

Additional embodiments are described and shown in detail herein. Onemechanism to recognize tissue contact in this system is movement ordisplacement of the electrode relative to a catheter body interface.Upon such occurrence, an output signal can be generated to allow foraudible, visual tactile, and/or other user feedback when a desiredcontact has been achieved between the electrode and the tissue, possiblyabove a predetermined threshold. This feedback, which may be varied, isprovided through loads applied to sensors, including strain and pressuregauges, piezoelectric transducers, microelectromechanical systems(MEMS), optical or laser displacement transducers, linear voltagedisplacement transducers, microphones, among other devices.

The foregoing and other aspects, features, details, utilities, andadvantages of the present invention will be apparent from reading thefollowing description and claims, and from reviewing the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic and block diagram view of a system incorporatingan embodiment of a medical device having a contact sensing electrodeassembly.

FIG. 2 is a cross-sectional view of an embodiment of the electrodeassembly of the medical device of FIG. 1 configured to use vibration anddeflection sensing to sense contact.

FIGS. 3 and 4 are cross-sectional views of other embodiments of theelectrode assembly of the medical device of FIG. 1 configured to usedeflection sensing to sense contact.

FIG. 5 is a cross-sectional view of another embodiment of the electrodeassembly of the medical device of FIG. 1 configured to use vibration anddeflection sensing to sense contact.

FIGS. 6-9B are cross-sectional views of other embodiments of theelectrode assembly of the medical device of FIG. 1 configured to usedeflection sensing to sense contact.

FIG. 9C is an exemplary layout for transducers in the embodiment of theelectrode assembly of the medical device of FIGS. 9A and 9B fordeflection sensing.

FIGS. 10-12 are cross-sectional views of other embodiments of theelectrode assembly of the medical device of FIG. 1 configured to usedeflection sensing to sense contact.

DETAILED DESCRIPTION

Referring now to the drawings wherein like reference numerals are usedto identify identical components in the various views, FIG. 1 generallyillustrates a system 10 having a catheter electrode assembly 11configured to be used in the body for medical procedures. The electrodeassembly 11 is included as part of a medical device such as a catheter19 and may be used for diagnosis, visualization, and/or treatment oftissue 13 (such as cardiac or other tissue) in the body. For example,the electrode assembly 11 may be used for ablation therapy of tissue 13or mapping purposes in a patient's body 14. FIG. 1 further shows varioussub-systems included in the overall system 10. The system 10 may includea main computer system 15 (including an electronic control unit 16 anddata storage 17, e.g., memory). The computer system 15 may furtherinclude conventional interface components, such as various userinput/output mechanisms 18 a and a display 18 b, among other components.Information provided by the electrode assembly 11 may be processed bythe computer system 15 and may provide data to the clinician via theinput/output mechanisms 18 a and/or the display 18 b, or in other waysas described herein.

In the illustrative embodiment, the catheter 19 may include a cableconnector or interface 20, a handle 21, a tubular body or shaft 22having a proximal end 23 and a distal end 24. The catheter 19 may alsoinclude other conventional components not illustrated herein such as atemperature sensor, additional electrodes, and corresponding conductorsor leads. The connector 20 may provide mechanical, fluid and/orelectrical connections for cables 25, 26 extending from a fluidreservoir 12 and a pump 27 and the computer system 15, respectively. Theconnector 20 may comprise conventional components known in the art and,as shown, may be disposed at the proximal end of the catheter 19.

The handle 21 provides a portion for a user to grasp or hold thecatheter 19 and may further provide a mechanism for steering or guidingthe shaft 22 within the patient's body 14. For example, the handle 21may include a mechanism configured to change the tension on a pull-wireextending through the catheter 19 to the distal end 24 of the shaft 22or some other mechanism to steer the shaft 22. The handle 21 may beconventional in the art, and it will be understood that theconfiguration of the handle 21 may vary. In an embodiment, the handle 21may be configured to provide visual, auditory, tactile and/or otherfeedback to a user based on information received from the electrodeassembly 11. For example, if contact to tissue 13 is made by theelectrode assembly 11, the handle 21 may include light-emitting-diodes,a tone generator, a vibrating mechanical transducer, and/or otherindicator(s), the outputs of which could vary in proportion to thesignal sensed at the electrode assembly.

Referring to FIG. 2, a cross-sectional view of an embodiment of a distalportion of a catheter 19 having an electrode assembly 11 ^(A) isgenerally illustrated. The electrode assembly 11 ^(A) may be connectedto the tubular body 22 ^(A) of the catheter 19 and located distal froman end of the tubular body 22 ^(A). The tubular body 22 ^(A) can be anelongate tubular body, in some examples. The electrode assembly 11 ^(A)may comprise an electrode 31 ^(A), a vibration element 32, a deformablemember 35 ^(A), and a deflection measuring sensor 33 ^(A).

The electrode 31 ^(A) may include an electrode tip 34 ^(A) and anelectrode base 36 ^(A), which can form a single, integral component. Insome embodiments, the electrode tip 34 ^(A) may be configured to contactan object. The object can include, for example, tissue 13 of a patient.In some embodiments, the electrode tip 34 ^(A) can be configured tocontact a medium. The medium can include, for example, blood of apatient or a saline solution. As used herein, the terms “object” and“medium” are meant to include both items in which the catheter tip maybe immersed, as well as items against which the catheter tip may betouched and exert a force.

The vibration element 32 may be driven by an electrical signal tovibrate the electrode 31 ^(A) with a vibration inducing signal to inducevibration of the electrode 31 ^(A). The electrode 31 ^(A) can bevibrated by the vibration element 32 at a frequency, for example, aresonant frequency of the electrode tip 34 ^(A), which depends on themechanical structure of the electrode 31 ^(A). The vibration element 32can also be configured to vibrate the electrode 31 ^(A) at a particularamplitude and/or phase. In an example, the vibration element 32 can be atransducer that converts the electrical signal into mechanical energy(e.g., vibrations).

When the electrode tip 34 ^(A) comes into contact with the object and/ormedium, the frequency, amplitude, and/or phase of the resonant vibrationof the electrode tip 34 ^(A) may be changed (e.g., dampened). Forexample, prior to contact occurring between the electrode tip 34 ^(A)and the object and/or medium, the electrode assembly 11 ^(A) can vibrateat a particular frequency, amplitude, and/or phase. However, uponcontact between the electrode tip 34 ^(A) and the object and/or medium,energy can be imparted from the electrode tip 34 ^(A) to the object inthe form of vibrations, thus changing the particular frequency,amplitude and/or phase at which the electrode tip 34 ^(A) is vibrating.In addition, as a force between the object and the electrode tip 34 ^(A)is increased, more vibrations can be absorbed by the object, thusdampening vibration of the electrode and causing a perturbation.Increasing the force between the object and the electrode tip 34 ^(A)can place a larger surface area of the electrode tip 34 ^(A) in contactwith the object, thus increasing an amount of vibrations that areabsorbed by the object.

The perturbation (e.g., changed frequency, amplitude, phase at which theelectrode tip 34 ^(A) is vibrating, electrical drive signal) may besensed either through the electrical drive signal or through a secondsensor (not shown) located near the vibrating electrode 31. The secondsensor can be configured to monitor the electrode 31 ^(A) for aperturbation in the induced vibration of the electrode 31 ^(A). Forexample, the second sensor can be configured to sense a change in thefrequency, amplitude, and/or phase at which the electrode tip 34 ^(A) isvibrating at before contact with the object and/or medium and aftercontact with the object and/or medium. In addition, upon contact of theelectrode tip 34 ^(A) with the object and/or medium, the electricaldrive signal may change. For example, upon contact of the electrode tip34 ^(A) with the object and/or medium, a change in energy used to drivethe electrode tip 34 ^(A) may occur, as a result of energy beingimparted from the electrode tip 34 ^(A) to the object and/or medium. Assuch, the change in energy may be reflected by a change in currentand/or voltage used to vibrate the electrode tip 34 ^(A), which can besensed.

The frequency, amplitude, and/or phase of vibration of the electrode tipcan be dampened by different amounts, depending on what type of objectand/or medium the electrode tip 34 ^(A) contacts. For example, asdiscussed herein, when the electrode tip 34 ^(A) contacts tissue 13, aparticular amount of energy can be imparted to the tissue 13 from theelectrode tip 34 ^(A), thus dampening the vibration of the electrode tip34 ^(A). The amount of energy imparted to the tissue 13, however, can bedifferent than an amount of energy imparted to blood or another type ofmedium that the electrode tip 34 ^(A) contacts in route to a targetedsite within the body. For example, a mechanical property (e.g., density)of air is different than a mechanical property of saline solution, whichis different than a mechanical property of blood, which is differentthan a mechanical property of tissue 13. These different mechanicalproperties can lead to a different change in vibration of the electrodetip 34 ^(A), as the electrode tip 34 ^(A) comes into contact withdifferent regions of a patient's vasculature and/or anatomy.

In some embodiments, when the electrode tip 34 ^(A) comes into contactwith different types of objects and/or media (e.g., tissue 13, blood,saline solution, air), a change in vibration that occurs when crossingfrom one type of medium to the next may be reproducible. For example,when the electrode tip 34 ^(A) crosses an air-blood interface,blood-tissue interface, or air-tissue interface; for example, thevibration of the electrode tip 34 ^(A) may be reduced by a particularamount that is reproducible. Particular devices can be calibrated tofactor in what type of interfaces (e.g., air-blood, blood-tissue,air-tissue) that the device will be operating in. As such, if in aparticular procedure, the electrode assembly 11 ^(A) will be crossing ablood-tissue interface, the electrode assembly 11 ^(A) can be calibratedfor this and can accurately correlate a dampening of the vibration tocontact with the tissue 13. Alternatively, if in a particular procedure,the electrode assembly 11 ^(A) will be crossing an air-tissue interface,the electrode assembly 11 ^(A) can be appropriately calibrated for thisand can accurately correlate a dampening of the vibration to contactwith the tissue 13.

In some embodiments, the vibration element 32 can be configured tomaintain the induced vibration after contact between the electrode 31^(A) and the object and/or medium. For example, the vibration element 32can be configured to maintain a particular frequency, particularamplitude, and/or particular phase of the vibration inducing signal uponcontact between the electrode 31 ^(A) and the object and/or medium. Theparticular frequency, particular amplitude, and/or particular phase canbe maintained by varying an electrical drive signal of the vibrationelement 32. Increasing contact (e.g., magnitude of force) between theelectrode 31 ^(A) and the object can result in changing (e.g.,increasing) the electrical drive signal to maintain asubstantially-steady-state vibration of the electrode 31 ^(A). Thechange to the electrical drive signal can be monitored with a sensor,for example, a current sensor.

The magnitude of change of the dampened frequency, amplitude, and/orphase of the vibration and/or change in electrical drive signal may beused to determine whether contact has occurred between the electrode tip34 ^(A) and tissue 13. As used herein, contact can be defined as contactbetween the electrode tip 34 ^(A) and tissue 13, a magnitude of forceapplied between the electrode tip 34 ^(A) and tissue 13, and/or a vectorof force applied to the electrode tip 34 ^(A) as a result of contactbetween the electrode tip 34 ^(A) and tissue 13. For example, inresponse to the frequency, amplitude, and/or phase changing by a definedamount, a determination that contact has occurred can be made (e.g., yesor no). Alternatively, the magnitude of change of the dampenedfrequency, amplitude, and/or phase of the vibration and/or the change inthe electrical drive signal may be correlated to a magnitude of forceapplied between the electrode tip 34 ^(A) and tissue 13. As describedmore fully below, the vibration element 32 may be driven at anypredetermined frequency, and not necessarily at a resonant frequency,where vibrations sensed by the second sensor may exhibit discernibledifferences in responsive vibration characteristics (e.g., frequency,amplitude, and/or phase) upon contact between the electrode 31 ^(A) andtissue 13, which can be analyzed to determine contact (e.g., whethercontact has occurred, magnitude of force corresponding to contact).

In an example, as pressure is applied to the handle 21, increasingcontact (e.g., magnitude of force) between the electrode tip 34 ^(A) andthe tissue 13, vibrations produced by the vibration element 32 can beabsorbed by the tissue 13. As such, the frequency, amplitude, and/orphase at which the electrode tip 34 ^(A) is vibrating, can be reduced.Alternatively, as pressure applied to the handle 21 is decreased,decreasing contact (e.g., magnitude of force) between the electrode tip34 ^(A) and the tissue 13, vibrations can be less absorbed by the tissue13. Therefore, the frequency, amplitude, and/or phase may be reducedless.

The electrode tip 34 ^(A) may be configured for axial movement M_(A) andlateral movement M_(L) relative to the electrode base 36 ^(A). Aclearance gap 38 may exist between a portion of the electrode tip 34^(A) and the electrode base 36 ^(A) to accommodate any axial and lateralmovements M_(A), M_(L) of the electrode tip 34 ^(A) relative to theelectrode base 36 ^(A). The electrode base 36 ^(A) may be configured tosecurely connect to a distal end of the tubular body 22 of the catheter19. A portion of the electrode base 36 ^(A) may be inserted into thetubular body 22.

The electrode tip 34 ^(A) may also have a channel 37 ^(A) (or aplurality of channels as shown in FIG. 5) configured to allow a fluid toflow through or adjacent to the electrode tip 34 ^(A), such as forirrigation purposes. The electrode base 36 ^(A) may further include achannel 39 configured to allow a fluid to flow from a lumen in thetubular body 22, through the electrode base 36 ^(A), and to theelectrode tip 34 ^(A), and may be used for irrigation purposes. Thechannel 37 ^(A) can line up with the channel 39 to some degree at alllateral movements of the electrode tip 34 ^(A) relative to the electrodebase 36 ^(A).

The electrode tip 34 ^(A) may be connected to the electrode base 36 ^(A)via a spherical joint 40 ^(A). The spherical joint 40 ^(A) may comprisea spherical knuckle 41 ^(A) located in a pocket 42 ^(A). The pocket 42^(A) may be substantially cylindrical in shape. In an embodiment, theknuckle 41 ^(A) may be a portion of the electrode base 36 ^(A) and thepocket 42 ^(A) may be a cavity located in the electrode tip 34 ^(A). Inanother embodiment (as generally illustrated in FIG. 3), the knuckle 41^(A) may be a portion of the electrode tip 34 ^(A) and the pocket 42^(A) may be a cavity located in the electrode base 36 ^(A).

The vibration element 32 may be configured to vibrate the electrode tip34 ^(A) at a defined frequency, amplitude, and/or phase of vibration.The vibration element 32 may be fixedly or rigidly connected to theelectrode tip 34 ^(A), such that vibrations produced by the vibrationelement 32 are transferred to the electrode tip 34 ^(A) via a contactpoint between the vibration element 32 and the electrode tip 34 ^(A). Insome embodiments, the vibration element 32 may be located in the pocket42 ^(A). The vibration element 32 may be annular and may besubstantially similar in diameter to the pocket 42 ^(A). The vibrationelement 32 may include an aperture located in the center of thevibration element 32. The aperture may be used to allow fluid to passthrough the vibration element 32. The aperture may be substantially thesame diameter as the channel 37 ^(A) located in the electrode tip 34^(A). The vibration element 32 may be located in the pocket in theelectrode tip 34 ^(A), at a distal position relative to the knuckle 41^(A). Alternatively, the vibration element 32 may be located in thepocket 42 ^(A) in the electrode base 36 ^(A), at a proximal positionrelative to the knuckle 41 ^(A) (as generally illustrated in FIG. 3).While a detailed embodiment of a vibration element is provided, it willbe appreciated that this disclosure is not limited to the illustratedembodiments. Rather, other types and forms of vibration inducingtransducers, including those known to those with skill in the art, maybe used.

In embodiments, the second sensor may be configured to measure thefrequency, amplitude, and/or phase of the vibration of the electrode tip34 ^(A). When the electrode tip 34 ^(A) is not in contact with tissue13, the second sensor may detect a frequency, amplitude, and/or phasesubstantially equal to a frequency (which may be predefined orpredetermined), amplitude, and/or phase imparted to the electrode tip 34^(A) by the vibration element 32. When the electrode tip 34 ^(A) is incontact with tissue 13, the second sensor may detect changes infrequency, amplitude, and/or phase. The changes might be positive ornegative depending on the specific design of the resonating structure,but the magnitude of the change will be proportional to a magnitude offorce applied between the electrode tip 34 ^(A) and tissue 13.

In some examples, the second sensor can be annular in shape. The secondsensor can be located on the electrode tip 34 ^(A); located distallywith respect to the spherical knuckle 41 ^(A) in a pocket of theelectrode tip 34 ^(A); or located proximally with respect to thespherical knuckle 41 ^(B) in the pocket of the electrode base 36 ^(B),as shown in FIG. 3.

In an embodiment, the system 10 may be programmed to determine whethercontact between the electrode tip 34 ^(A) and tissue 13 has occurred.For example, a determination that contact has occurred between theelectrode tip 34 ^(A) and the tissue 13 can be made in response to adifferential between a first and second frequency, amplitude, and/orphase of vibration being exceeded. The first frequency, amplitude,and/or phase of vibration can be a frequency, amplitude, and/or phasethat exists when the electrode tip 34 ^(A) is not in contact with tissue13 and the second frequency, amplitude, and/or phase of vibration can bea frequency, amplitude, and/or phase that exists when the electrode tip34 ^(A) is in contact with tissue 13. In some embodiments, the first andsecond frequency, amplitude, and/or phase can be correlated with a firstand second magnitude of force applied between the electrode tip 34 ^(A)and tissue 13.

This allows the system 10 to be adjustable for determining the amount offorce between the electrode tip 34 ^(A) and tissue 13 that must occurbefore the system acknowledges that contact with tissue 13 has occurred.For example, if the differential between the first and second frequency,amplitude, and/or phase of vibration is set high, then the magnitude offorce applied between the electrode tip 34 ^(A) and tissue 13 e tosufficiently determine that contact has been made may be high inmagnitude. Additionally, if the differential between the first andsecond frequency, amplitude, and/or phase of vibration is set low, thenthe amount of contact force to sufficiently determine that contact hasbeen made may be low in magnitude.

In some embodiments, the electrode assembly 11 ^(A) can include adeformable member 35 ^(A) and a deflection measuring sensor 33 ^(A), asfurther discussed in relation to FIG. 3. The deformable member 35 ^(A)and the deflection measuring sensor 33 ^(A) can be configured to measurea lateral displacement M_(L) (e.g., angular) and axial displacementM_(A) of the electrode tip 34 ^(A) relative to the electrode base 36^(A).

The deflection measuring sensor 33 ^(A) and/or the deformable member 35^(A) may be annular in shape and may be provided in the pocket 42 ^(A)in the electrode tip 34 ^(A). The deflection measuring sensor 33 ^(A)and/or the deformable member 35 ^(A) may be provided at a positiondistal to the knuckle 41 ^(A). In another embodiment (as generallyillustrated in FIG. 3), the deflection measuring sensor 33 ^(A) and/orthe deformable member 35 ^(A) may be located proximal to the knuckle 41in the pocket 42 ^(B) in the electrode base 36 ^(B). In yet anotherembodiment, the deflection measuring sensor 33 ^(A) may be apiezoelectric transducer.

In some embodiments, the deflection measuring sensor 33 ^(A) and/or thesecond sensor may send a signal to the handle 21 and/or control unit 16,upon determining that contact has been made between the electrode tip 34^(A) and the tissue 13, or when the magnitude of force applied betweenthe electrode tip 34 ^(A) and tissue 13 is greater than a definedamount. The signal to the handle 21 may be used to provide a requiredamount of haptic or visual feedback via the handle 21 (which may havebeen configured as previously described). The signal to the control unit16 may be used to provide information to the user, such as through thevarious input/output devices 18 a or the display 18 b of the system 10.

As generally shown in FIG. 3, an embodiment of an electrode assembly 11^(B) may also be configured to measure lateral displacement M_(L) (e.g.,angular) and axial displacement M_(A) of the electrode tip 34 ^(B)relative to an electrode base 36 ^(B). The magnitude of thedisplacements M_(L), M_(A) may be used to determine contact between theelectrode tip 34 ^(B) and tissue 13, a magnitude of force appliedbetween the electrode tip 34 ^(B) and tissue 13, and/or a vector offorce applied to the electrode tip 34 ^(B) as a result of contactbetween the electrode tip 34 ^(B) and tissue 13. In an embodiment, theelectrode assembly 11 ^(B) may comprise the electrode 31 ^(B) having theelectrode tip 34 ^(B) and the electrode base 36 ^(B), a deformablemember 35 ^(B), and a deflection measuring sensor 33 ^(A).

The deformable member 35 ^(B) is configured to deform when a force isapplied between the electrode tip 34 ^(B) and tissue 13. The deformablemember 35 ^(B) may be located adjacent to a flat portion of the knuckle42 ^(B). As the electrode tip 34 ^(B) makes contact with tissue 13, theelectrode tip 34 ^(B) will move relative to the electrode base 36 ^(B).Depending on the angle at which the electrode tip 34 ^(B) contacts thetissue 13, the electrode tip 34 ^(B) may move either axially M_(A)and/or laterally M_(L) relative to the electrode base 36 ^(B). When theelectrode tip 34 ^(B) moves axially M_(A) and/or laterally M_(L) bypivoting about the spherical joint 40 ^(B), the deformable member 35^(B) may be squeezed against the flat portion of the knuckle 41 ^(B) anda rigid surface, such as a wall 45 of the electrode base 36 ^(B) (asshown in FIG. 3) or a surface of the vibration element 32 (as shown inFIG. 2). In some embodiments, the deformable member 35 ^(B) can expandradially outward. When the electrode tip 34 ^(B) is no longer in contactwith tissue 13, the deformable member 35 ^(B) can elastically return toits initial form. The deformable member 35 ^(B) may be annular in shapeand may have an aperture located at the center of the deformable member35 ^(B) which may allow fluid to pass through the deformable member 35^(B). The deformable member 35 ^(B) may be provided or positioned in thepocket 42 ^(B) of the electrode tip 34 ^(B) between the knuckle 41 ^(B)and the electrode base 36 ^(B).

In another embodiment, shown in FIG. 3, the deformable member 35 ^(B)may be provided or positioned in the pocket 42 ^(B) of the electrodebase 42 ^(B) between the knuckle 41 ^(B) and the wall 45 of theelectrode base 36 ^(B). The amount of force necessary to deform thedeformable member 35 ^(B) may be set or determined based on a selectionof a material used for the deformable member 35 ^(B). For example, asthe selected material of the deformable member 35 ^(B) becomes stifferand more difficult to deform, the amount of force necessary to deflectthe electrode tip 34 ^(B) may also increase. This may be useful, forexample, in setting or determining the range of forces to be measured.In embodiments, the deformable member 35 ^(B) may comprise silicon,rubber, or other natural and manmade elastomeric materials. A widevariety of other elastically deformable materials may be used as knownto those with skill in the art.

The deflection measuring sensor 33 ^(B) may be configured to measure thedeformation of the member 35 ^(B). As the deformable member deforms(e.g., expands radially), the deflection measuring sensor 33 ^(B) maydetect the deformation of the deformable member 35 ^(B). The deflectionmeasuring sensor 33 ^(B) may be located on the deformable member 35 ^(B)and may be coaxial with the deformable member 35 ^(B) and surround thedeformable member 35 ^(B). The deflection measuring sensor 33 ^(B) maybe annular in shape. In an embodiment, the deflection measuring sensor33 ^(B) may be a piezoelectric transducer configured for measuringstrain. The magnitude of deformation of the deformable member 35 ^(B)detected by the deflection measuring sensor 33 ^(B) may correlate to avector of force applied to the electrode tip 34 ^(B) as a result ofcontact between the electrode tip 34 ^(B) and tissue 13. The deflectionmeasuring sensor 33 ^(B) may send a signal to the handle 21 and/or thecontrol unit 16. The signal to the handle 21 may be used to provide aset or required amount of haptic or visual feedback for which the handle21 may be configured to produce. The signal to the control unit 16 maybe used to provide information to a user, such as through the variousinput/output devices 18 a or the display 18 b of the system 10.

The deformable member 35 ^(C) may have various shapes. For example, asgenerally illustrated in FIG. 4, the deformable member 35 ^(C) may be abeam that is generally linear shaped, such as substantially cylindricalshaped or substantially rectangular shaped. The deformable member 35^(C) may be provided or positioned distally of the knuckle 41 ^(C) andprovided or positioned in the pocket 42 ^(C). One end of the deformablemember 35 ^(C) may be connected to the knuckle 41 ^(C) and the opposingend of the member may be connected to the electrode tip 34 ^(C). Thedeformable member 35 ^(C) can be longitudinally arranged along alongitudinal centerline of the catheter 19, extending from a distal endof the knuckle 41 ^(C) to a distal end of the pocket 42 ^(C). Theelectrode tip 34 ^(C) can be deflected axially M_(A) or laterally M_(L),causing deformation of the deformable member 35 ^(C). The deflectionmeasuring sensor 33 ^(C), provided or positioned on deformable member 35^(C) may measure the deformation of the deformable member 35 ^(C).

In an embodiment, and as generally illustrated in FIG. 5, an electrodeassembly 11 ^(D) may comprise an electrode 31 ^(D) having an electrodetip 34 ^(D) and an electrode base 36 ^(D), a deformable member 35 ^(D),a deflection measuring sensor 33 ^(D), a vibration element 32 ^(D) and avibration measuring sensor 49.

The electrode assembly 11 ^(D) may be configured to determine contactbetween the electrode tip 34 ^(D) and tissue 13, a magnitude of forceapplied between the electrode tip 34 ^(D) and tissue 13, and/or a vectorof force applied to the electrode tip 34 ^(D) as a result of contactbetween the electrode tip 34 ^(D) and tissue 13 by both vibrationdampening sensing of the electrode tip 34 ^(D) and strain deflectionmeasurements of the deformable member 35 ^(D), such as generallydescribed with reference to FIGS. 2 and 3. By using both vibrationdampening sensing of the electrode tip 34 ^(D) and strain deflectionmeasurements of the deformable member 35 ^(D), the accuracy and/or rangeof measurements associated with determining contact between theelectrode tip 34 ^(D) and tissue 13, magnitude of force applied betweenthe electrode tip 34 ^(D) and tissue 13, and/or the vector of forceapplied between the electrode tip 34 ^(D) and tissue 13 may beincreased. For example, the vibration measuring sensor 49 may beconfigured to measure small magnitudes of force applied between theelectrode tip 34 ^(D) and tissue 13, while the deflection measuringsensor 33 ^(D) may be configured to measure larger magnitudes of forceapplied between the electrode tip 34 ^(D) and tissue 13. The vibrationmeasuring sensor 49 may be provided or positioned directly on theelectrode tip 34 ^(D). The deflection measuring sensor 33 ^(D) may belocated directly on the deformable member 35 ^(D).

In yet another embodiment illustrated in FIG. 6, an electrode assembly11 ^(E) may comprise electrode 31 ^(E) having an electrode tip 34 ^(E)and an electrode base 36 ^(E). The electrode assembly 11 ^(E) mayfurther comprise a spherical joint 53, a beam 54 positioned distally ofthe spherical joint 53, one or more strain gauges 55 and a cavity 56. Asshown, one end of the beam 54 may be connected to the spherical joint 53and the other end of the beam 54 may be connected to the electrode 31^(E) at or near the electrode tip 34 ^(E).

The electrode assembly 11 ^(E) may be configured to measure contactbetween the electrode tip 34 ^(E) and tissue 13, a magnitude of forceapplied between the electrode tip 34 ^(E) and tissue 13, and/or a vectorof force applied to the electrode tip 34 ^(E) as a result of contactbetween the electrode tip 34 and tissue 13 since any applied force onthe electrode tip 34 ^(E) causes deflection in the beam 54, whichgenerates feedback through the one or more strain gauges 55. Based onthis embodiment, a determination can be made whether the force appliedbetween the electrode tip 34 ^(E) and the tissue 13 is an axial force ora lateral force. Further, the one or more strain gauges 55 may bereplaced with piezoelectric transducers, or other sensors to determinethe contact between the electrode tip 34 ^(E) and tissue 13, themagnitude of force applied between the electrode tip 34 ^(E) and tissue13, and/or the vector of force applied to the electrode tip 34 ^(E) as aresult of contact between the electrode tip 34 ^(E) and tissue 13.

In yet another embodiment illustrated in FIG. 7, an electrode assembly11 ^(F) may comprise electrode 31 ^(F) having an electrode tip 34 ^(F),an electrode base 36 ^(F), a standoff 58, a first piezoelectrictransducer 59, a second piezoelectric transducer 60, a seal 61, and acavity 62. The electrode tip 34 ^(F) can move laterally with respect tothe electrode base 36 ^(F) at a center of rotation 63. The electrode 31^(F) is connected to the electrode base 36 ^(F) at the standoff 58 andthe seal 61, such that when a force is applied to the electrode tip 34^(F), either an axial force or a lateral force, the standoff impinges onthe first piezoelectric transducer 59.

In operation, the second piezoelectric transducer 60 is electricallydriven at a known frequency and the first piezoelectric transducer 59 isset up to recognize the output of the second piezoelectric transducer60. When the electrode tip 34 ^(F) is in contact with the tissue 13, theresponse output of the first piezoelectric transducer 59 will changewith the applied load or tone of the tissue as a lesion is developed.The output of the first piezoelectric transducer 59 may be used toprovide a signal for audible, visual, tactile, and/or other feedback tothe user as described above. In some embodiments, the firstpiezoelectric transducer 59 can be configured to recognize an output ofthe second piezoelectric transducer 60. The output recognized by thefirst piezoelectric transducer 59 can be correlated to the magnitude ofthe contact force applied to the electrode tip 34 ^(F). Further, thesecond piezoelectric transducer 60 may be optional and the firstpiezoelectric transducer 59 may be replaced with a strain gauge.

In yet another embodiment, illustrated in FIG. 8, an electrode assembly11 ^(G) may comprise electrode 31 ^(G) having an electrode tip 34 ^(G),and an electrode base 36 ^(G), a seal 65, a fluid or gel 66, a straingauge 67, and a cavity 68. The space between the electrode tip 34 ^(G)and the electrode base 36 ^(G) is filled with the fluid 66, which isretained in the cavity 68 by the seal 65. The fluid 66 has significantelectrical resistance or impedance such that the closer the electrodetip 34 ^(G) comes to the electrode base 36 ^(G), the lower theresistance. Depending on where contact occurs between the electrode tip34 ^(G) and the tissue 13, a distance between the electrode tip 34 ^(G)and the electrode base 36 ^(G) can decrease, thus reducing the amount offluid 66 and electrical resistance or impedance between a particularpoint of the electrode tip 34 ^(G) and the base. A number of sensors(e.g., current sensors) can be placed on the electrode base 36 ^(G),which can detect changes in current resultant from the varying distancebetween the electrode tip 34 ^(G) and the electrode base 36 ^(G). Thedetected changes in current can be correlated with measurements ofcontact between the electrode tip 34 ^(G) and tissue 13, a magnitude offorce applied between the electrode tip 34 ^(G) and tissue 13, and/or avector of force applied to the electrode tip 34 ^(G). As discussedherein, the measurement can be based on capacitance and/or impedanceassociated with the fluid 66.

Further, the strain gauge 67 may measure the force on the electrode base36 ^(G) (or on the electrode tip 34 ^(G)) as the distance or thicknessof space between the electrode tip 34 ^(G) and the electrode base 36^(G) changes. A number of strain gauges 67 can be placed on theelectrode base 36 ^(G) in the cavity 68. In an example, as force isapplied to the electrode tip 34 ^(G), a pressure in the cavity 68 canincrease and can be registered by one of the number of strain gauges 67and correlated with a magnitude of force and/or a vector of forceapplied to the electrode tip 34 ^(G). Depending on where the force isapplied to the electrode tip 34 ^(G), one strain gauge 67 may register agreater pressure increase than another, providing for omni-directionalmeasurement of force on the electrode tip 34 ^(G).

As described above, when the electrode tip 34 ^(G) is in contact withthe tissue 13, the response output will change with the applied load ortone of the tissue as a lesion is developed. As with the embodimentsdescribed herein, the principles can be used for measuring changes intissue tone as a means for assessing lesion development. Given that themechanical characteristics of the tissue changes during and following RFablation, the described embodiments could also be used to monitor theextent (e.g., size) of a lesion by recognizing changes in the feedbackthru the transducers, strain gauges, or the like.

In yet another embodiment illustrated in FIG. 9A, an electrode assembly11 ^(H) may comprise electrode 31 ^(H) having an electrode tip 34 ^(H)and an electrode base 36 ^(H). Similar to the embodiments shown in FIGS.3 and 5, a knuckle 72 is incorporated along with a gap 73 ^(A) betweenthe electrode tip 34 ^(H) and the electrode base 36 ^(H). As furthershown in FIG. 9B, a strain gauge 74 is located in the gap 73 ^(B)between the electrode tip 34 ^(I) and the electrode base 36 ^(I).Lateral movement of the electrode tip 34 ^(I) relative to the base 36^(I) can change a size of the gap 73 ^(B), which can be registered bythe strain gauge 74. In some embodiments, multiple strain gauges 74 canbe located in the gap 73 ^(B) in a radial configuration. For example,strain gauges 74 can be located in one of three places, each 120° fromeach other, as shown in the layout in FIG. 9C. Other configurationsusing more or fewer than three transducers may be utilized with similarresults. As described herein, the strain gauges 74 may be replaced withpiezoelectric transducers, or various other types of sensors MEMS, LVDT,optical, laser, etc., configured to measure an increase or decrease in asize of the gap 73 ^(B). Upon contact between the electrode tip 34 ^(H)and the tissue 13, the strain gauges 74 (or transducers) will provide asignal for audible, visual, tactile and/or other feedback to the user asdescribed above.

In yet another embodiment illustrated in FIG. 10, an electrode assembly11 ^(J) may comprise electrode 31 ^(J) having an electrode tip 34 ^(J),and an electrode base 36 ^(J). The electrode tip 34 ^(J) can have afirst diameter and can be connected to a beam 81 of a second diameter ata proximal end of the electrode tip 34 ^(J). The electrode base 36 ^(J)includes an opening of a varying diameter passing from a proximal end toa distal end of the electrode base 36 ^(J). The diameter of the openingat the distal end of the electrode base 34 ^(J) can be smaller than thefirst diameter of the electrode tip 34 ^(J) and larger than the seconddiameter of the beam 81. The beam 81 can be inserted into the opening ofthe distal end of the electrode base 36 ^(J).

The electrode assembly 11 ^(J) further comprises a transducer 78, whichcan be annular in shape, a compliant or deformable member 79, and atensioned assembly 80. The tensioned assembly may be made up of the beam81, similar to the beam in FIG. 6 and a band 82 stretched between thebeam 81 and an end piece 83. The transducer 78 may be of any type oftransducer that can sense a change in tension in the band 82, such as astrain gauge, piezoelectric, MEMS, LVDT, optical, laser, etc. Uponcontact between the electrode tip 34 ^(J) (or the electrode 31 ^(J)) andthe tissue 13, the deformable member 79 can deform causing the tensionedassembly 80 to increase or decrease the amount of tension on the band82. The transducer 78 will sense the change in tension and provide anoutput signal 84 for audible, visual, tactile and/or other feedback tothe user as described above. For example, an increase or decrease in theamount of tension on the band 82 can pull the end piece 83 towards adistal end of the electrode tip 34 ^(J), causing the end piece 82 toexert an increase or decrease in amount of force applied to thetransducer 78. The transducer 78 can sense the increase or decrease inthe amount of force applied on the transducer 78 and/or can sense thechange in tension in the band 82, which can be used to determine contactbetween the electrode tip 34 ^(J) and tissue 13, a magnitude of forceapplied between the electrode tip 34 ^(J) and tissue 13, and/or a vectorof force applied to the electrode tip 34 ^(J).

In yet another embodiment illustrated in FIG. 11A, an electrode assembly11 ^(K) may comprise electrode 31 ^(K) having an electrode tip 34 ^(K)of a first diameter, and an electrode shaft 88 of a second diameter.Electrode assembly 11 ^(K) may further comprise a compliant or softmaterial 89, such as silicone, a piezoelectric receiver transducer 90^(A), and a piezoelectric transmitter transducer 91 ^(A). The electrodeshaft 88 can be connected to the electrode tip 34 ^(K). In addition, thepiezoelectric receiver transducer 90 ^(A) can be attached to a proximalend of the electrode shaft 88. The electrode shaft 88 and thepiezoelectric receiver transducer 90 ^(A) can be inserted into anopening at a distal end of an electrode base 94. In an example, thediameter of the opening at the distal end of the electrode base 94 canbe smaller than the first diameter of the electrode tip 34 ^(K) andlarger than the second diameter of the electrode shaft 88.

An application of force to the electrode tip 34 ^(K) can move theelectrode tip 34 ^(K), the electrode shaft 88, and the piezoelectricreceiver transducer 90 ^(A) proximally towards the piezoelectrictransmitter transducer 91 ^(A), such that the transducers contact oneanother, creating a signal which can be correlated with the applicationof force to the electrode tip 34 ^(K).

The piezoelectric receiver transducer 90 ^(B) and piezoelectrictransmitter transducer 91 ^(B) are represented schematically in FIG. 11Balong with the connections for the signal into the transmitter 92 andthe signal out from the receiver 93. Additional embodiments are shown inFIG. 11C (indicating a pressure amplification due to a small contactarea) and FIG. 11D (alternative transducer arrangements). For example,as the piezoelectric receiver transducer 90 ^(C) moves towards andcontacts the piezoelectric transmitter transducer 91 ^(C), thepiezoelectric receiver transducer 90 ^(C) can contact the piezoelectrictransmitter transducer 91 ^(C) with a reduced contact area, leading to apressure amplification between the point of the piezoelectric receivertransducer 90 ^(C) and the piezoelectric transmitter transducer 91 ^(C).The pressure amplification between the piezoelectric receiver transducer90 ^(C) and the piezoelectric transmitter transducer 91 ^(C) can providean increase in sensitivity. In some embodiments, the piezoelectricreceiver transducer 90 ^(D) can have a female contact face and thepiezoelectric transmitter transducer 91 ^(D) can have a male contactface. Alternatively, the piezoelectric receiver transducer 90 ^(E) canhave a female contact face and the piezoelectric transmitter transducer91 ^(E) can have a male contact face. In an example, the alternativetransducer configurations in FIG. 11D can provide for a differentsensitivities. As also described herein, the piezoelectric transducers90 ^(A), 91 ^(A) may be replaced with strain gauges, MEMS microphones,LVDT, optical, laser, etc. Upon contact between the electrode tip 34^(K) and the tissue 13, the electrode shaft 88 will move accordingly,such movement will be picked-up by the transducers, which will generatea signal as described above.

In yet another embodiment illustrated in FIG. 12, an electrode assembly11 ^(L) can include an electrode 31 ^(L) having an electrode tip 34^(L), an electrode base 96, a beam 98, swivel joint 99, and straingauges 97. The electrode 31 ^(L) can be connected to the beam 98 at aproximal end of the electrode 31 ^(L). The beam 98 can extend through aportion of a length of the electrode base 96. In some embodiments, theelectrode base 98 can be cylindrical and can have tapered inner walls,such that a distal opening of the electrode base 96 is substantially thesame size as the beam 98 and a proximal opening of the electrode base 96is larger than the distal opening. This can allow for movement of thebeam 98 when deflection of the electrode tip 34 ^(L) occurs. Theelectrode base 96 can be in contact with the electrode 31 ^(L) via aswivel joint 99. Movement of the beam 98 can be detected by straingauges 97 in contact with the beam 98 and the electrode base 96. Forexample, lateral movement of the electrode tip 34 ^(L) caused by contactwith tissue 13 can also cause movement of the beam 98, which can bedetected by sensors 97. An output of the sensors 97 can be used todetermine contact between the electrode tip 34 ^(L) and tissue 101, amagnitude of force applied between the electrode tip 34 ^(L) and tissue101, and/or a vector of force applied to the electrode tip 34 ^(L).

As discussed herein, the amount of energy imparted to the tissue 101 canbe different than an amount of energy imparted to medium 100 (e.g.,blood) that the electrode tip 34 ^(L) contacts in route to a targetedsite within the body. In an example, the electrode tip 34 ^(L) canpenetrate medium 100 to contact tissue 101. Mechanical properties of thetissue 101 and medium 100 can lead to a different change in vibration ofthe electrode tip 34 ^(L), as the electrode tip 34 ^(L) comes intocontact with different regions of a patient's vasculature. Accordingly,the electrode assembly 11 ^(L) can be calibrated to account fordifferent types of media that the electrode tip 34 ^(L) will contact, asdiscussed in relation to FIG. 2.

Various embodiments are described herein to various apparatuses,systems, and/or methods. Numerous specific details are set forth toprovide a thorough understanding of the overall structure, function,manufacture, and use of the embodiments as described in thespecification and illustrated in the accompanying drawings. It will beunderstood by those skilled in the art, however, that the embodimentsmay be practiced without such specific details. In other instances,well-known operations, components, and elements have not been describedin detail so as not to obscure the embodiments described in thespecification. Those of ordinary skill in the art will understand thatthe embodiments described and illustrated herein are non-limitingexamples, and thus it can be appreciated that the specific structuraland functional details disclosed herein may be representative and do notnecessarily limit the scope of the embodiments, the scope of which isdefined solely by the appended claims.

Reference throughout the specification to “various embodiments,” “someembodiments,” “one embodiment,” or “an embodiment,” or the like, meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.Thus, appearances of the phrases “in various embodiments,” “in someembodiments,” “in one embodiment,” or “in an embodiment,” or the like,in places throughout the specification are not necessarily all referringto the same embodiment. Furthermore, the particular features,structures, or characteristics may be combined in any suitable manner inone or more embodiments. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment may be combined, in whole or in part, with the features,structures, or characteristics of one or more other embodiments withoutlimitation given that such combination is not illogical ornon-functional.

It will be appreciated that the terms “proximal” and “distal” may beused throughout the specification with reference to a clinicianmanipulating one end of a medical device or instrument used to treat apatient. The term “proximal” refers to the portion of the device closestto the clinician and the term “distal” refers to the portion locatedfurthest from the clinician. It will be further appreciated that forconciseness and clarity, spatial terms such as “vertical,” “horizontal,”“up,” and “down” may be used herein with respect to the illustratedembodiments. However, medical devices may be used in many orientationsand positions, and these terms are not intended to be limiting orabsolute.

Although only certain embodiments have been described above with acertain degree of particularity, those skilled in the art could makenumerous alterations to the disclosed embodiments without departing fromthe scope of this disclosure. Joinder references (e.g., attached,coupled, connected, and the like) are to be construed broadly and mayinclude intermediate members between a connection of elements andrelative movement between elements. As such, joinder references do notnecessarily infer that two elements are directly connected/coupled andin fixed relation to each other. Additionally, the terms “electricallyconnected” and “in communication” are meant to be construed broadly toencompass both wired and wireless connections and communications. It isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative only andnot limiting. Changes in detail or structure may be made withoutdeparting from the invention as defined in the appended claims.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

What is claimed is:
 1. A catheter comprising the following: an elongatetubular body comprising a distal end; a spherical joint comprising ajoint proximal end and a joint distal end, the joint proximal endconnected to the distal end of the elongate tubular body; a catheter tipconnected to the joint distal end, wherein the spherical joint isconfigured to allow relative movement between the catheter tip and theelongate tubular body; a deformable member disposed adjacent to thespherical joint, wherein: the elongate tubular body, the catheter tip,the spherical joint, and the deformable member are configured to beinserted into a patient's body via the patient's vasculature; andmovement of the spherical joint causes the deformable member to deform;and a deflection measuring sensor configured to measure a deformation ofthe deformable member.
 2. The catheter of claim 1, wherein: thespherical joint includes a knuckle; and a deformable member is disposedadjacent to the knuckle.
 3. The catheter of claim 2, further comprisinga deflection measuring sensor configured to measure a deformation of thedeformable member.
 4. The catheter of claim 2, wherein a proximal end ofthe knuckle is connected to a distal end of a base and the base isconnected to the distal end of the elongate tubular body.
 5. Thecatheter of claim 4, wherein the deflection measuring sensor isconfigured to measure a magnitude of displacement between the cathetertip and the base.
 6. The catheter of claim 5, wherein the magnitude ofdisplacement between the catheter tip and the base is representative ofa magnitude of force applied between the catheter tip and a tissue of abody.
 7. The catheter of claim 5, wherein the magnitude of displacementbetween the catheter tip and the base is representative of a vector offorce applied to the catheter tip.
 8. The catheter of claim 1, wherein:the deformable member is configured to deform in response to a forcebeing applied between the catheter tip and a tissue; and the elongatetubular body and the catheter tip are directly connected via thespherical joint.
 9. The catheter of claim 8, wherein the deflectionmeasuring sensor comprises a piezoelectric transducer.
 10. The catheterof claim 1, wherein the deformable member is formed from an elastomericmaterial.
 11. The catheter of claim 1, wherein: the spherical jointincludes a knuckle connected to a distal end of the elongate tubularbody; and the deformable member is disposed between the knuckle and thecatheter tip.
 12. A catheter comprising the following: an elongatetubular body comprising a distal end; a spherical joint comprising ajoint proximal end and a joint distal end, the joint proximal endconnected to the distal end of the elongate tubular body, wherein thespherical joint includes a knuckle; an electrode tip connected to thejoint distal end, wherein the spherical joint is configured to allowrotational hinging between the electrode tip and the elongate tubularbody; and a deformable member disposed between the knuckle and theelectrode tip, the deformable member in contact with the knuckle and theelectrode tip, wherein; the elongate tubular body, the catheter tip, thespherical joint, and the deformable member are configured to be insertedinto a patient's body via the patient's vasculature; and movement of thespherical joint causes the deformable member to deform.
 13. The catheterof claim 12, further comprising a deflection measuring sensor configuredto measure a deformation of the deformable member, wherein thedeflection measuring sensor is configured to measure a lateraldisplacement and axial displacement of the electrode tip.
 14. Thecatheter of claim 13, wherein the deformable member is configured todeform when a force is applied between the electrode tip and a tissue.15. The catheter of claim 13, wherein the elongate tubular body and theelectrode tip are directly connected via the spherical joint.
 16. Anelectrode assembly, comprising: an electrode tip configured to deliverenergy to a tissue, the electrode tip being connected to a distal end ofa catheter configured for insertion into a patient's body via thepatient's vasculature; an electrode base slidingly coupled with theelectrode tip; a first piezoelectric transducer connected with theelectrode tip; and a second piezoelectric transducer coupled with theelectrode base, wherein the electrode tip and the first piezoelectrictransducer are configured to longitudinally slide towards the secondpiezoelectric transducer in response to an application of force to theelectrode tip, wherein: the piezoelectric transmitter transducer and thepiezoelectric receiver transducer generate a signal in response to theapplication of force to the electrode tip, the signal representative ofthe application of force; and a force applied to the electrode tip isdetermined based on the signal representative of the application offorce.
 17. The electrode assembly of claim 13, wherein the firstpiezoelectric transducer is a receiver and the second piezoelectrictransducer is a transmitter.
 18. The electrode assembly of claim 17,wherein the piezoelectric transmitter transducer is held in fixedrelation to the electrode base.
 19. The electrode assembly of claim 13,wherein the piezoelectric receiver transducer and the piezoelectrictransmitter transducer generate the signal as a result of contactbetween the piezoelectric receiver transducer and the piezoelectrictransmitter transducer.